mypy: Enable new error explicit-override.

Signed-off-by: Anders Kaseorg <anders@zulip.com>

zerver/management/commands/check_redis.py

@@ -5,6 +5,7 @@ from typing import Any, Callable, Optional
 from django.conf import settings
 from django.core.management.base import BaseCommand, CommandError, CommandParser
 from returns.curry import partial
+from typing_extensions import override
 
 from zerver.lib.rate_limiter import RateLimitedUser, client
 from zerver.models import get_user_profile_by_id
@@ -16,6 +17,7 @@ class Command(BaseCommand):
 
     Usage: ./manage.py [--trim] check_redis"""
 
+    @override
     def add_arguments(self, parser: CommandParser) -> None:
         parser.add_argument("-t", "--trim", action="store_true", help="Actually trim excess")
 
@@ -46,6 +48,7 @@ than max_api_calls! (trying to trim) %s %s",
                 client.expire(key, entity.max_api_window())
                 trim_func(key, max_calls)
 
+    @override
     def handle(self, *args: Any, **options: Any) -> None:
         if not settings.RATE_LIMITING:
             raise CommandError("This machine is not using Redis or rate limiting, aborting")